By now, these guys know one another well. They are buds. Or, in the Aussie vernacular, they’re mates.

The four natives of Sydney, Australia, known as Human Nature are tight with the man who has bestowed his name and tacit endorsement on their show at The Venetian, Motown legend Smokey Robinson. When they convene, there is no divide between their ages or cultures or position in the history of pop music.

Two of the members of Human Nature are brothers -- Andrew and Mike Tierney -- but when assembled, they share a brotherhood. They talk of music and presentation, and they do like to laugh.

A meeting Friday afternoon at Sands Showroom, hours before Human Nature was to formally premiere their new, spiffed-up production at The Venetian, offered such a moment. The five men were to take part in a photo shoot onstage posing beneath the show’s giant “Motown” sign. Placed at the side was an old-style, stand-up microphone used in the show, and Robinson said, “Bring that over here.”

Phil Burton retrieved the prop and Robinson said, “Grab it at the stem.”

At which point, one of the guys -- and we’ll give Toby Allen credit for this, as it is a prime example of his fast-response sense of humor -- replied, “That’s what she said!”

The guys busted out in laughter.

Four years after debuting at Imperial Palace, in a theater that would later be named for them, Human Nature has moved to a comparably lavish venue. Conceived by highly regarded set designer Andy Walmsley, the stage flashes with neon-like lights and is backed and flanked by video screens. The stage has been built with multiple platforms to allow for movement at varying heights. At one point, an old 8-mm film projector is rolled out to play home movies of the group’s early days in Australia, where they don wide-brimmed hats, suspenders and skinny ties and sing in almost-perfect harmony.

Robinson came into play after hearing of this group’s spot-on rendition of Motown classics. He had to see them in person, to decide if they merited the onerous endorsement “Smokey Robinson Presents,” which would doubtless give them a boost in their far-off goal to build a career in the United States.

They put on quite a show, singing “Tracks of My Tears” a cappella and displaying their now-familiar dance steps.

“I’m not prejudiced by any stretch of the imagination, but to see four white boys singing and dancing like that, and doing the music like that, I’d never seen that before,” Robinson says during a group interview in the Sands Showroom dressing room. “They came so self-ready, that’s what made them different. What they sang for me in the studio, just to hear them sing like that, was just incredible. With a lot of acts -- especially throughout the course of my life -- you have to work with them, you have to tweak this and tweak that, but these guys were ready.”

What was needed was a stamp of approval. For Robinson’s, his is an entirely personal endorsement.

“My only involvement was to try to get them into the United States and let people have a chance to see who they are and what they do,” Robinson says. “They speak for themselves.”

They sing for themselves, too. Human Nature is a group of four guys who have no subs. There is no swing Toby, or two guys playing the role of Andrew. Their work ethic is as impressive as their finely honed singing voices. The guys dance at a frenetic pace and often hit the gym before or after the performance. This is especially true of Andrew Tierney, who looks as if he can run a triathlon at any walking moment.

“I’ll talk to these guys and ask, ‘What did you do today? and they’ll say, ‘I went to the gym, I worked out,’ ” Robinson says, laughing. “What? Why? What about tonight? You’re going to be at the gym tonight? After what you do onstage? My God! Why?”

To keep in physical condition is the chief reason. By their own count, Human Nature has canceled no more than a half-dozen shows in their entire run in Las Vegas. This doesn’t count trips back to Australia or performances across the country.

“As far as staying healthy, we’re lucky in that if someone is a little bit sick, just has a cold or something, we can still go on and cover him,” Burton says. “If one of us says, ‘I can’t sing,’ then we’re over. We’re canceled.”

The Motown/Human Nature connection developed organically. The classics of such famed groups as Smokey Robinson and The Miracles, The Temptations, The Supremes, Marvin Gaye, The Four Tops and The Marvelettes fit the guys’ collective singing styles. It also was a convenient way to reach an international audience in a way singing their own original songs could not.

But Human Nature didn’t embrace Motown to simply become famous.

“It wasn’t a conscious feeling -- we didn’t do our first Motown record for that reason. We just did it because we love the music, and it was the music that inspired us to be who we are,” Andrew Tierney says. “Once we did it and we saw the success of the record, there was this weird connection. We wondered, are we going to become known just because we did this one record? But it created a whole new career for us as we were interpreting this music.

“It would have taken a genius to sit down and say, ‘Look, you guys should do this.’ We would have said, ‘You’re crazy.’ ”

During Friday’s opening night, the four Aussies brought out their friend Smokey to the stage. They had already performed a duet with an early 1960s version of Robinson on the video screens. But the real deal strode to the stage for “Get Ready.” The place went nuts, the crowd standing and dancing along with the song.

Not many acts could stand with Smokey Robinson and perform that song. But this crew from Australia, on its dazzling stage with their mate from Motown, looked right at home.